Proposal of novel process to concentrate valuable metals and to remove impurity elements from wasted PCBs

Takeru Sugisawa, Taku Seo, Kazuma Tsutsumi, Shuji Owada, Tokoro Chiharu, Satoshi Kawakami, Shota Tahata

Research output: Contribution to conferencePaper

Abstract

Recycling of various metals involved in the electronic printed circuit boards (PCBs) is important. However, PCBs contain not only valuable metals, Cu and precious/rare metals, but also the elements, Al, Br, Sb, etc., which adversely affect the following non-ferrous metals smelting operation. Most of the conventional PCB recycling processes, involving crushing and physical separation, have not taken care on such elements. This study presents a knowledge of PCB recycling, to concentrate valuable metals and remove such impurity elements, by combining roasting, selective crushing and physical separation. It was determined that an appropriate roasting condition was approx. 300 C at air atmosphere to make brittle the resins composed of the PCB and to decompose flame retardants, Br and Sb. It was also found important to apply two-stage comminution, which involves cutting into the pieces of appropriate size in the first stage and liberating E-glass fiber from resin in the PCB without flocculating E-glass in the second stage. The subsequent physical separation process could concentrate of 38.9 wt% Cu with the recovery of 80.3 % and reduce Al by 64.7 %, Br by 75.1 % and Sn by 50.2 %.

Original languageEnglish
Publication statusPublished - 2020
Event15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019 - Pyeongchang, Gangwon-do, Korea, Republic of
Duration: 2019 Oct 132019 Oct 17

Conference

Conference15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019
CountryKorea, Republic of
CityPyeongchang, Gangwon-do
Period19/10/1319/10/17

Keywords

  • Roasting
  • Two-stage comminution
  • Wasted PCBs

ASJC Scopus subject areas

  • Environmental Science(all)

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  • Cite this

    Sugisawa, T., Seo, T., Tsutsumi, K., Owada, S., Chiharu, T., Kawakami, S., & Tahata, S. (2020). Proposal of novel process to concentrate valuable metals and to remove impurity elements from wasted PCBs. Paper presented at 15th International Symposium on East Asian Resources Recycling Technology, EARTH 2019, Pyeongchang, Gangwon-do, Korea, Republic of.